In some aircraft engines, bleed air is taken off at the 5th compressor stage and supplied to a plenum for air frame use. The bleed air is taken through a metering gap between the outer compressor stator casing and the inner compressor stator casing. The metering passage is intended to pass about 5% of the total compressor air flow to the air frame plenum. It has been difficult to control the area of the bleed passage due to mechanical stackup and thermal growth of the outer and inner casings. Also, the continuous gap allows wakes and swirls in the orifice flow path which lowers the stall margin.